British journal of anaesthesia
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Observational Study
Transient electroencephalographic alpha power loss during maintenance of general anaesthesia.
EEG activity in the extended alpha frequency range (7-17 Hz) during maintenance of general anaesthesia is primarily determined by effect-site concentrations of the hypnotic and analgesic drugs used. Intermittent alpha loss during surgery, unexplained by changes in anaesthetic or opioid concentrations, could represent arousal of the cortex as a result of increased surgical stimulation. ⋯ A loss of alpha power, unexplained by changes in anaesthetic or opioid concentrations, is suggestive of thalamocortical depolarisation induced by body cavity noxious stimuli, and could provide a measure of nociception during surgery.
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Observational Study
Non-invasive continuous detection of arterial hypotension during induction of anaesthesia using a photoplethysmographic signal: proof of concept.
During general anaesthesia, intraoperative hypotension (IOH), defined as a mean arterial pressure (MAP) reduction of > 20%, is frequent and may lead to complications. Pulse oximetry is mandatory in the operating room, making the photoplethysmographic signal and parameters, such as relative dicrotic notch height (Dicpleth) or perfusion index (PI), readily available. The purpose of this study was to investigate whether relative variations of Dicpleth and PI could detect IOH during anaesthesia induction, and to follow their variations during vasopressor boluses. ⋯ NCT03756935.